Collective cell migration is essential during development as well as in adult organisms where it participates, for instance, in tissue renewal, wound healing or cancer invasion and metastasis. As cells migrate collectively, intercellular junctions maintain the integrity of the cell monolayer while allowing differential movement and rearrangements of adjacent cells. In astrocytes, intercellular contacts are mainly formed by N-cadherin-mediated adherens junctions. Downregulation of N-cadherin is frequently observed in astrocyte derived tumors, gliomas and promotes single cell migration while perturbing cell polarity and increasing cell velocity.

To understand how cells can maintain stable intercellular junctions and simultaneously rearrange them to accommodate cellular displacement, we have investigated cadherin dynamics during astrocyte collective migration. We show adherens junctions undergo a continuous retrograde movement compensated by a polarized recycling of cadherin from the rear to the leading edge. Such dynamics allows the cells to maintain stable contacts while permitting changes of cellular interactions. In glioma cells, N-cadherin dynamics and consequently the maintenance of cell-cell contacts are perturbed leading to loss of cell polarity and to increased migration.